Aeronautical propeller



0a. 16, 1928. S. A. REEDv AERONAUTICAL PROPE'LLER Filed May, 12, 1924ATTORNEY j f QIBWE TOR OZ v Patented Oct. 16, 1 928.

; UNITED STATES PATE O F SYLVANUS A; REED,',OF new YORK, iv. Y.,'Assreivon TO THE REED rRornLLnR o0. me, on NEW YORK, n. Y., ACORPORATION or NEW Y R -j .AERONAU TIQAL PROPELLER.

Application. w ma '12,

cation for patent, filled June 22, 1922, Serial No. 570,139, Idisclose-certain types of metal 5 aeronautical propellers, and mypresent im#.

shaft-hole bored through the propeller, boltprovements are alsoapplicable tosaid gen-'- eral types, but,'of course, are not in any Waylimited thereto.- f t My present invention includes ii-simplificationofstructure whereby omitting ,the'

featuresneeded for interchangeabilitywith customary wooden propellers onthe same steel hubs a propeller may. be Obtained of greater efficiencyand strength with less ag-, gregate weight. In some of my earlier formsof structure, the above mentioned-adaptabilityfor attachmerit toexisting steelhubs employed a cen tralexpansion ,to permit ma ing alarge central hole to pass the end of the driving-shaft and smallerholes for thevhub-bolts; In my present improvements, there is no centralholes are reduced in number and long bolts are dispensed with. But moreparticularly. I-

gain inthe total efiiciency, because of-a'closer approximation which Iam able to obtain to a true helix nearly up to. the drive shaft-itself.I'also gain the propulsive effect ofjthe blades up to those points andinaddition I- r gain by the omission of a central boss which" is anobstruction to flight, is anadditional weight andabsorbs a certainamount of the driving power. p A true helical propeller passes'throughthe driving axis in such a manner thatthe driving or thrust face is-at apitch-angleof 90?, and that'type of section of a helical surface whichconstitutes an ideal propeller will'be found to have aroundthe-longitudinal or di ametrical axis of the propellen-a continuoustwist, always in the same direction, right or left-handed, from onetip'through the driveshaft axis to the other tip. In my said patent andpatent application, in order to -ac commodate the central shaft-holeandcustomary huh, I reversed this twist near the central region or huband resumed the original twist beyond. In my present improvements I havea continuous twist in one direction from tip to tip of the'blades,

No.:"1,463,5 56,'"dated July 31, 1923, and also in my pending app li-1924. Seria1No.712,tl 16.

I It isfobvious soform-a propeller by twisting a; ,sing-leflpieee ofelongated metal plate and teprevide the same with the usual camberfaceforward-and a flat face on thethrust side,the plate before twisting,as above described, will have the saidchamber 0f one'blade on one sideof the original plate and'thecamberof the otherblade on the reverse sideof the plate, Them-after twist,

tothe appropriate pitch, always in one direction, both-camber faces willbe found on the same side namely, the forward: side of.

theftwisted propeller. a i l In order to secure the propeller to ICE.

t the driveshaftforsafe transmission oftorque and thrust several means,are available with the ,pec'uliar construction and arrangement. of

this propeller, butI prefer, where possible, to omit theusual'drive-shaft extension'and to terminate. the driveshaft closeto itsfor ward bearing and secure thereto a metal body or shell, preferably ofsteel, with inclined side-slots, to receive andhold securely thepropeller blades in position, said shell having a medial re-inforcingring or strap, pref- .erably of steel, passing through holes in thepropeller and; assisting in looking it securely in'place. a With theseand other objects in view, my

inventionswill be'more fully described, illustrated in the drawings andthen particularly pointed out in the claims.

r In the said drawings anddrive-shaft, with the attaching body or shelland its adjuncts in longitudinal section. t Fig. 2, is an underside viewof the propeller Fig. 1, is'a side elevation of the propeller and itsshaft-attaching means, with the shaft I omitted. v v t Fig. 3,-is a sideelevation of the structure,

the view being at right-angles to that shown in Fig. 1.f.

Referring to the drawings '1 is a portion. of the outer end-of thepropeller drive-shaft, and 2 is a flange on the end thereof. The

a central connecting part 5, which contains or includes, indicated .bythe line 77, the

axis ofthe propeller shaft, the arrow 6, showboss near the centralregion, as in the case of 100 propeller is formed with blades 3 and 4,with wooden propellers, or of being reversed intwist asin the case ofcertain forms of my metal propeller requiring a central shafthole,

my improvedpropeller-blades continue toinj crease their pitch-anglessothat at the point 7, at'the axial line, they are at 90, and it isnotedjthat'the direction of the twist around the longitudinal axis,indicated by the line 8.8 isinxone direction from tip to tip, and thatthe leading-edge9, of each blade crosses over the axial line to becomethe leading-edge 9, of the other, and as the trailing-edge 10, likewisecrosses over to become the trailing edge 10, of theother, the forwardblade faces after twisting, as shown in view in Fig. 2, are

it is secured by short bolts 14. At dia-- metrically opposite points,the walls of shell 12, are formed with inclined slots 15, closelyfitting the central part 5, of thepropeller which is inserted edgewiseinto the same from the lower open ends'of the slots. The upper ends ofthe slots are closed and the length of the .slots being the width of thecentral f no blade-connecting part 5, the inner edge of said part isdrawnifirmly against the shaft flange 2, by the bolts HQ These slots 15,extend longitudinally of the sleeve and in oblique direction and aremade to accurately fit' and accommodate the part 5, which passestransversely through the shell or hub 12.

A- metal strap or ring 19, is passed around the exterior of the tubularhub 12, and

"through snugly fitting holes 16, formed in the central part 5,atopposite sides of said hub. The ends of the strap are drawn togetherand secured by bolting or welding, thus strengthening the. shell 12, andat the same time,

fixing the propeller against end play. The

strap 19, may also be secured to the shell by screws 20, to anchor itsecurely in place. The propeller is thus held firmly against thrust andtorque and relies for resistance to centrifugal force solely uponits ownintegrity without participation of the member or hub 12, which maytherefore be made relatively light in weight.

- The outer end of theshell is provided with i a finishing cap 17, inthe form of a hollow cone of thin material telescopedover the end,

and secured thereto by screws, 18, and serving to diminish airresistance.

This' novel form of propeller permits of the same being mountededge-wise'in respect to the drive-shaft, so that the axis of rotation iscoincident with the transverse axis of the eration.

'entis:

propeller. This disposition of the propeller i not only results in alighter weight structure,

but also simplifies the same, at thesametime giving certain advantagesin elli'ciency of op- 'My invention is not confined-to the par ,ticularconstructions of part's,:as herewith disclosed, as various modificationsmay be made in several different parts, without, however, departing fromthe spirit of my invention.

The propeller is made preferably of a solid metal plateand of any wellknown suitable light-weight metal alloys, such asaluminum al oys, forexample duralumin. I Having thus'described my inventiomwhat I claim anddesire to secure by Letters Pat- .1. An aeronautical propeller having a.

- nonaxially perforated central part and oppositely extendingbladesconnected therewith and crossing the driving-axisso that said axisis parallel with the wide dimension of said central part and saidpropeller twisted so that the trend of the twist is substantiallycontinuous from end to end to equal result-ant pitch-angles for eachblade with the convex faces of both blades disposed on the same side ofthe propeller;

2. A single piece metal aeronautical propeller formed from an elongatedrelatively thin nonaxially perforated plate with blades convex on oneside of one blade and convex on the other side of the other blade, andtwisted in one direction from end to end to equal resultant pitch-anglesfor each blade.

3. A single piece metal aeronautical propeller formed from an elongatedrelatively thin nonaxially perforated plate with oppositely extendingblades convex on one side of one blade and convex on the other side ofthe other blade, and twisted in one direction from tip to tipto equalresultant pitch-angles for each bladeso that both convex faces are onthe forward side of. the propeller.

4. An aeronautical propeller having a helical twist about itslongitudinal axis and formed from a blank having acentral part withblade portions connected therewith and convex on one side of one bladeportion and convex on the other side of the other blade and a hubdriving-memberconstructed and arranged so that said central part ofthepropeller passes transversely through it in locking engagementtherewith to'transmit torque and thrust,- said fiat central part lyingsub: stantially along the axis ofrotation, and

means for securing said central part against movement relativelyto saiddriving-member. '6. A propeller having a comparatively this cent a Pa toh ch th bl des are centhereof so that the transverse axis of saidcentral part is coincident with said drivingaxis, and means for securingsaid parts together.

8. A propeller having a central part to which the blades are connected,a hub comprising a body provided with a transverse passage extendingalong the axis of the hub for receiving said central part, said centralpart extending through said passage, and

means for securing said parts together.

9. A propeller having a central part to which the blades'are connected,a hub comprising a body having a flange at its inner end and providedwith a transverse'opening for receiving said central part, said centralpart extending through said opening and means for locking the partstogether, a driveshaft provided with a flange and means for attaching itto the flange of said hub body.

10. A propeller having a central part to which the blades are connected,a hub comprising a body having a transverse opening extending through itfor receiving said central part, said central part extending throughsaid opening, orifices in said central part-upon each side of said bodyto the exterior thereof, and locking members passing through saidorifices and secured to said hub bod 11 A propeller having a centralpart to which the blades are connected, a hub comprising a body having atransverse passage therethrough for receiving said central part, saidcentral part passing through said passage in the body, said central partbeing formed with orifices lying to the exterior of said body, and alocking-member passing around said body and through the respectiveorifices and secured in such position.

12. A propellerhaving a ccntra'l part to which the blades are connected,a hub comprising a tubular body, similarly disposed slots formed in theopposite walls of said body and open at one end thereof, but closed atthe other, and said central part being inserted in said slots, and aclosure for, the open ends of said slots.

13. A propeller having a central part to which the blades are connected,a hub com-- prising a tube flanged at its inner end and provided in itsopposite walls with simi-- larly arranged slots which open at said innerend of the tube, said central part being mounted in said slots andfitting the same, perforations formed in said central part tothe'exterior of said tube, a strap passing around said, tube and throughsaid perforations in the central part and secured to said tube.

14:. A propeller having a central bladeconnecting part with oppositelyextending blades and twisted in one direct-ion from end to end to equalresultant pitch-angles for each blade so that the leading edge of oneblade passes through the driving-axis and becomes the leading edge ofthe other blade, a hub comprising abody provided with a transversepassage for receiving said central part, said central part being mountedthrough said passage and containing said drivingaxis, and means forsecuring said parts to gether.

15. In an aeronautical propeller, a broad and comparatively thin centralnonaxially perforated mounting, part having blades connected therewithand crossing the driving-axis so that the broad dimension issubstantially parallel with said driving-axis, and driving connectionsengaging the broad faces or sides of said central-part for drivingthesame. I

16. In an aeronautical propeller, a nonaxially perforated centralmounting part formed broad and comparatively thin and having bladesattached thereto and crossing the driving-axis so that the broaddimension is substantially parallel with said drivingaxis, and drivingconnections for said part comprising a member provided with a passageaxially coincident with said driving-axis and having oppositely arrangedopenings through which said central-part extends with practicallyunobstructed spaces at the sides of said central-part in the region ofthe drivlng-axis.

17.. An aeronautical propeller having a central mounting part connectingthe oppo sitely extending blades, the propeller being of helical formabout its longitudinal axis from tip to tip of the blades, and a tubulardriving-member having the said central part secured diametrically acrossthe tubular member so as to leave the opposite sides of said centralpart unobstructed within the tubular member.

In testimony whereof, I have hereunto set I

